Immunotranscriptome analysis of Plutella xylostella reveals differences in innate immune responses to low‐ and high‐virulence Beauveria bassiana strain challenges

Abstract

BACKGROUND Entomopathogenic fungi have developed multiple strategies to overcome the immune defenses of their target insects, whereas insect pests have devised various defense mechanisms to combat fungal infection. However, differences in the molecular mechanisms of the innate immune defense strategies of insects upon infection with different fungal strains from the same species have not been reported. RESULTS Two Beauveria bassiana strains were obtained that significantly varied in their pathogenicity but were comparable in terms of growth, conidial yield, and cuticle penetration. To investigate the molecular mechanisms underlying the immune response of Plutella xylostella infected with these two strains, RNA‐Seq was performed 48 h after infection. A total of 1027 differentially expressed genes (DEGs) were identified, and more than 200 DEGs were enriched in Kyoto Encyclopedia of Genes and Genome (KEGG) pathways involved in disease response, revealing differences in the immune response of P. xylostella to different B. bassiana infections at 48 h. Twenty‐eight of the DEGs were related to innate immune functions, such as pathogen recognition, immune system activation and antimicrobial reactions. RNA interference (RNAi)‐mediated gene silencing assays showed that PxApoLIII and PxCSP played critical roles in the P. xylostella immune response. PxApoLIII was expressed at higher levels during infection with the high‐virulence strain, whereas PxCSP showed the opposite expression pattern during infection with the low‐virulence strain, indicating that PxApoLIII and PxCSP might participate in P. xylostella innate immune defense against high‐ and low‐virulence B. bassiana strains. CONCLUSION The present findings demonstrate that strains of a single species of pathogenic fungi that differ in virulence can induce the expression of different genes in P. xylostella. These results advance our knowledge of the molecular mechanisms underlying fungi–pest interactions.

Comprehensive insights into host‐pathogen interaction between brown planthopper and a fungal entomopathogen by dual RNA sequencing

“…However, our results were not completely consistent with the results observed in the whitefly ( Bemisia tabaci )‐ B. bassiana interaction system, in which the relative abundances of most metabolism‐related genes displayed a trend of downregulation in the whitefly infected by B. bassiana when compared with the control 46 . This result suggested that the interaction mechanisms in different insect‐fungus systems were not conserved, which is consistent with the findings of recent studies focused on host‐pathogen interactions using models of the same host insect‐different fungi or different host insects‐same fungi 18,47 …”

“…46 This result suggested that the interaction mechanisms in different insect-fungus systems were not conserved, which is consistent with the findings of recent studies focused on host-pathogen interactions using models of the same host insect-different fungi or different host insects-same fungi. 18,47 For fungal DEGs involved in BPH-Ma456 interaction, most of the upregulated genes belonged to the functional category of ribosome biogenesis, suggesting that the fungal protein anabolism tended to be vigorous during the course of infection. It is generally known that entomopathogenic fungi produce many kinds of cuticle-degrading enzymes to facilitate penetration through the outmost cuticular barrier of the host, such as proteases, chitinases and lipolytic enzymes.…”

Variation in Bombyx mori immune response against fungal pathogen Beauveria bassiana with variability in cell wall β‐1,3‐glucan

“…B. bassiana strains, Bb6, Bb9, Bb11, and Bb20 were used in this study; they were stored at the Research Center for Entomogenous Fungi of Anhui Agricultural University, Anhui Province, China (Wang et al. , 2021c). All strains were stored in liquid nitrogen and transferred to Sabouraud dextrose agar with yeast extract (SDAY) in the dark at 25 °C for activation before use.…”

MicroRNA-like RNA Functions Are Required for the Biosynthesis of Active Compounds in the Medicinal Fungus Sanghuangporus vaninii

“…To silence different core components of the RNAi machinery in S . vaninii , dsRNAs targeting RNA-dependent RNA polymerase s, dicers , and argonautes were synthesized with T7 RNA polymerase (T7 RiboMAX Express RNAi system kit, Promega, Madison, WI, USA) based on established protocols ( 44 ). Briefly, ~300 bp DNA fragments, introduced at both the 5′ and 3′ ends with the T7 promoter sequence, were produced via PCR (PCR) from cDNA.…”